In this study, the epilithic diatoms were monthly investigated from five stations between September 2007 and April 2008 along the Murat Stream and 75 diatom taxa were totally identified. Among the stations, Cymbella affinis in M1, Gomphonema truncatum in M2, Diatoma moniliformis in M3, Gomphonema olivaceum in M4 and Fragilaria ulna in M5 were the most dominant species. Also, water quality of the Murat Stream was determined according to diatom taxa by using Håkansson, Lange-Bertalot, Hoffman, Van Dam and Watanabe Indices. The results show that, according to Håkansson’s Index, most of the species were alkaline characteristics; according to RoteListe of Lange-Bertalot Index approximately 51% of indicator species were described as “eutrophent”; according to Hoffman Index, the most of the indicator species were in the range of alfa- > beta- > βαmesosaprob; accrding to Van Dam Index, the most of the indicator species were the main groups of beta- than alphamesosaprobionts; and finally according to Watanabe Index, approximately 76% of indicator species were described as “indifferent.”